Two of the biggest smartphone-related announcements at the recently concluded Consumer Electronics Show (CES) came from Nokia and HTC, who unveiled Windows Phone 7.5 Mango-based devices - the Lumia 900 and the Titan II, respectively.

Although both devices support the lightning fast AT&T 4G LTE network, how do they stack up against the Samsung Focus S, one of the leading pre-CES Windows Phone smartphones?

Operating System: Basically, the OS is the only similarity between all three smartphones. All of them run on Windows Phone 7.5 Mango, which boasts features like dynamic Live Tile Information, Twitter and LinkedIn integration in the People hub, Facebook-events integrated calendar, threaded e-mail conversations support, visual voicemail, Outlook tasks support and much more. Other features of the OS include Shazam-like audio recognition, turn-by-turn Bing Maps navigation with voice guidance, Skydrive and Office 365 documents synchronization with PDF support, Microsoft Lync support, animated picture tiles, People/Groups gallery with Skydrive and Facebook sync, People Hub-integrated photo management, Zune SmartDJ multimedia mix support, video aspect ratio control capability while playback and more.

Display, Resolution and Dimensions: While all the three devices sport the same resolution - 480x800 pixels, the displays differ a little. The Nokia Lumia 900 sports a 4.3-inch ClearBlack AMOLED display and the HTC Titan II a 4.7-inch S-LCD display, while the Focus S sports a 4.3-inch Super AMOLED Plus display.

The Lumia 900 has dimensions of 127.8x68.5x11.5mm; unfortunately, it weighs a rather heavy 160 grams. The Focus S is the lightest of them all, tipping the scales at a mere 110.6 grams and dimensions of 126x66.8x8.5mm. The Titan II falls in between, measuring 132x69x13mm and weighing 147 grams.

Processor, RAM and Storage: While both the Samsung Focus S and Nokia's Lumia 900 are powered by a 1.4GHz Scorpion processor, the Focus S sports a slightly advanced 1.5GHz Scorpion processor. All three have a built in 512MB of RAM and 16GB internal storage capacity.

Camera: The Nokia Lumia 900 sports an 8 megapixel, 3264x2448 pixels, Carl Zeiss optics, autofocus, dual-LED flash primary rear camera with Geo-tagging and video recording capabilities of 720p at 30fps and video stabilization. The device also has a front-facing 1.3 megapixel secondary camera. The Samsung Focus S has a primary 8 megapixel, 3264x2448 pixels, autofocus, LED flash rear-facing camera with features like Geo-tagging, image stabilization and smile detection. A secondary 1.3 megapixel camera has also been provided. The HTC Titan II, on the other hand, sports a monstrous primary 16 megapixel, 4640 x 3480 pixels, autofocus and dual-LED flash rear camera with Geo-tagging, BSI sensor, image stabilization and face detection and a secondary 1.3 megapixel front-facing secondary camera.

Wi-Fi and Bluetooth: All three smartphones sport an 802.11 a/b/g/n Wi-Fi connection and while both the Titan II and the Lumia 900 have 2.1+A2DP Bluetooth, the Focus S has 3.0+A2DP, EDR Bluetooth.

Battery: The HTC Titan II has a standard Li-lon 1730 mAh battery. The Focus S, on the other hand, comes with a Li-lon 1650 mAh battery with stand-by of up to 250 hours and talk time up to 6 hours and 30mins. Compared to these, the Nokia Lumia N900 has a standard Li-lon 1830 mAh battery with up to 300 hours of stand-by, 7 hours of talk time and 60 hours of music play.

Sensors: The Lumia 900 has a gyroscope, an accelerometer, a digital compass and an ambient light sensor. The HTC Titan II lacks the light sensor, in comparison to the Lumia. Meanwhile the Focus S has only the accelerometer, a proximity sensor and a compass.

Price: Although nothing is known about the pricing of both the Lumia 900 and the Titan II, the Focus S (Wi-Fi only) is available for $199 on a two-year contract.

External Storage: None of the smartphones have the external storage options which could be a major problem for interested customers. This an area that could also hurt the three companies in their attempt to make a name for themselves in the smartphone market.